A Filtering Approach to Flood Routing

Hydrologic river routing and hydraulic channel routing are in general use for flood routing. Both approaches use deterministic mathematical models and treat inflow and outflow hydrographs for a given river reach as discrete time series. The former is based on the continuity equation and the latter solves the governing Saint-Venant equations numerically. Mathematical models are subject to errors in estimated model parameters, error in model structure, and error in numerical schemes used. In addition, errors in field measurements are virtually unavoidable. These errors may affect seriously the resulting flood hydrograph and should be dealt with in the solution. This paper combines a hydrologic river routing model and a filtering technique to provide optimal estimates of outflow hydrograph.